1. Field of the Invention
The present invention relates to a method of connecting a strip-like film and a connecting device thereof capable of being used in a form-fill-seal packaging machine enclosing commodities in packaging bags while form-fill-sealing a strip-like film into the packaging bags, or the like.
2. Description of the Related Art
As disclosed in, for example, Japanese Unexamined Patent Publication No. 1362/1991, there is known a form-fill-seal packaging machine in which a strip-like film is unreeled from a roll. The film is curved into a cylindrical shape at a downstream end portion of a running path while running the film along the running path. Mutually overlapped side edge portions and bottom end portions of the cylindrical film are respectively welded and sealed. Thereafter, commodities are supplied. Finally top end portions of the cylindrical film are welded, sealed and separated by cutting whereby the packaging bags enclosed with commodities are successively formed.
In such a form-fill-seal packaging machine, when the current film is exhausted, or the current film is interchanged with a film having a different design in accordance with the change of the enclosed commodities etc., or the like, the strip-like film or the film roll is interchanged. A number of members and devices including guide rollers, a forming unit curving the film into a cylindrical shape are installed along the feed path of the film, and the downstream end portion of the feed path where the bag forming packaging operation is carried out. Accordingly, it is very complicated and unpreferable to insert a new film along the feed path again after the running of the preceding film has been finished. Hence, it is known to bond the new or succeeding film to the preceding film at a position immediately after the film is unreeled out from the film roll and is made to run successively on the feed path under this state.
General technologies for connecting the succeeding new strip-like film to the preceding old strip-like film and manually switching or interchanging the strip-like film in this way are disclosed in, for example, Japanese Unexamined Patent Publication No. 59551/1992 and Japanese Unexamined Patent Publication No. 97122/1993.
However, all of the conventional technologies include a drawback in operational performance. Although in such a connecting operation, it is important for preventing wasteful use of the films and realizing stable connection of the films to minimize and always maintain as constant the overlap margin of the films, no conventional technologies satisfying such a request has yet been found.
Also, particularly in the case where limp or flexible films are connected manually, it is difficult to position the films in which the succeeding film is maintained in parallel with the preceding film. These films are made to overlap by a predetermined amount while the two side edge portions are being aligned. No proposal for technology capable of performing such an operation easily in a short period of time has currently been found.